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Audio between Raspberry Pi2 and EHS6 in call | Thales IoT Developer Community

April 2, 2020 - 12:01am, 786 views

Hi everyone.

I refer you to ask about a challenge I am having with the Gemalto EHS6 module. I am using a Raspberry Pi 2 with Ubuntu, to automate calls and SMS messaging using Python, my goal is to play a pre-recorded audio on calls and to be heard on the destination phone. So far, the transmission seems to be working, however the only thing you hear is noise during the call, there are no features to identify the recording, so I am having doubts if I am using the correct pins of the Gemalto GPIO.

From the Raspberry I am extracting the audio through PWM, and I am connecting it to the Gemalto GPIO21, which corresponds to RXDDAI, additionally I am linking the grounds between the Raspberry and the Gemalto.

Currently I have doubts about the GPIO22 (TFSDAI) and GPIO23 (SCLK) pins. Should they be used? Or are they only used to transmit from Gemalto to Raspberry?

Maybe if someone has done something similar, could you explain how you have done it to guide me a bit. I was guiding myself based on the following topic on this website: https://iot-developer.thalesgroup.com/tutorial/audio-codec-board-2g3g-terminal-pcm-interface

Thank you very much, greetings!